/*
 * ! Lazy Load - jQuery plugin for lazy loading images
 * 
 * Copyright (c) 2007-2015 Mika Tuupola
 * 
 * Licensed under the MIT license:
 * http://www.opensource.org/licenses/mit-license.php
 * 
 * Project home: http://www.appelsiini.net/projects/lazyload
 * 
 * Version: 1.9.7
 * 
 */
define(function(require) {
	return function(jQuery) {
(function($, window, document, undefined) {
			var $window = $(window);

			$.fn.lazyload = function(options) {
				var elements = this;
				var $container;
				var settings = {
					threshold : 0,
					failure_limit : 0,
					event : "scroll",
					effect : "show",
					container : window,
					data_attribute : "original",
					skip_invisible : false,
					appear : null,
					load : null,
					placeholder : ""
				};

				function update() {
					var counter = 0;

					elements.each(function() {
								var $this = $(this);
								if (settings.skip_invisible
										&& !$this.is(":visible")) {
									return;
								}
								if ($.abovethetop(this, settings)
										|| $.leftofbegin(this, settings)) {
									/* Nothing. */
								} else if (!$.belowthefold(this, settings)
										&& !$.rightoffold(this, settings)) {
									$this.trigger("appear");
									/*
									 * if we found an image we'll load, reset
									 * the counter
									 */
									counter = 0;
								} else {
									if (++counter > settings.failure_limit) {
										return false;
									}
								}
							});

				}

				if (options) {
					/* Maintain BC for a couple of versions. */
					if (undefined !== options.failurelimit) {
						options.failure_limit = options.failurelimit;
						delete options.failurelimit;
					}
					if (undefined !== options.effectspeed) {
						options.effect_speed = options.effectspeed;
						delete options.effectspeed;
					}

					$.extend(settings, options);
				}

				/* Cache container as jQuery as object. */
				$container = (settings.container === undefined || settings.container === window)
						? $window
						: $(settings.container);

				/*
				 * Fire one scroll event per scroll. Not one scroll event per
				 * image.
				 */
				if (0 === settings.event.indexOf("scroll")) {
					$container.bind(settings.event, function() {
								return update();
							});
				}

				this.each(function() {
					var self = this;
					var $self = $(self);

					self.loaded = false;

					/* If no src attribute given use data:uri. */
					if ($self.attr("src") === undefined
							|| $self.attr("src") === false) {
						if ($self.is("img")) {
							$self.attr("src", settings.placeholder);
						}
					}

					/* When appear is triggered load original image. */
					$self.one("appear", function() {
								if (!this.loaded) {
									if (settings.appear) {
										var elements_left = elements.length;
										settings.appear.call(self,
												elements_left, settings);
									}
									$("<img />").bind("load", function() {

										var original = $self.attr("data-"
												+ settings.data_attribute);
										$self.hide();
										if ($self.is("img")) {
											$self.attr("src", original);
										} else {
											$self.css("background-image",
													"url('" + original + "')");
										}
										$self[settings.effect](settings.effect_speed);

										self.loaded = true;

										/*
										 * Remove image from array so it is not
										 * looped next time.
										 */
										var temp = $.grep(elements, function(
														element) {
													return !element.loaded;
												});
										elements = $(temp);

										if (settings.load) {
											var elements_left = elements.length;
											settings.load.call(self,
													elements_left, settings);
										}
									}).attr(
											"src",
											$self.attr("data-"
													+ settings.data_attribute));
								}
							});

					/* When wanted event is triggered load original image */
					/* by triggering appear. */
					if (0 !== settings.event.indexOf("scroll")) {
						$self.bind(settings.event, function() {
									if (!self.loaded) {
										$self.trigger("appear");
									}
								});
					}
				});

				/* Check if something appears when window is resized. */
				$window.bind("resize", function() {
							update();
						});

				/*
				 * With IOS5 force loading images when navigating with back
				 * button.
				 */
				/* Non optimal workaround. */
				if ((/(?:iphone|ipod|ipad).*os 5/gi).test(navigator.appVersion)) {
					$window.bind("pageshow", function(event) {
								if (event.originalEvent
										&& event.originalEvent.persisted) {
									elements.each(function() {
												$(this).trigger("appear");
											});
								}
							});
				}

				/* Force initial check if images should appear. */
				$(document).ready(function() {
							update();
						});

				return this;
			};

			/* Convenience methods in jQuery namespace. */
			/*
			 * Use as $.belowthefold(element, {threshold : 100, container :
			 * window})
			 */

			$.belowthefold = function(element, settings) {
				var fold;

				if (settings.container === undefined
						|| settings.container === window) {
					fold = (window.innerHeight ? window.innerHeight : $window
							.height())
							+ $window.scrollTop();
				} else {
					fold = $(settings.container).offset().top
							+ $(settings.container).height();
				}

				return fold <= $(element).offset().top - settings.threshold;
			};

			$.rightoffold = function(element, settings) {
				var fold;

				if (settings.container === undefined
						|| settings.container === window) {
					fold = $window.width() + $window.scrollLeft();
				} else {
					fold = $(settings.container).offset().left
							+ $(settings.container).width();
				}

				return fold <= $(element).offset().left - settings.threshold;
			};

			$.abovethetop = function(element, settings) {
				var fold;

				if (settings.container === undefined
						|| settings.container === window) {
					fold = $window.scrollTop();
				} else {
					fold = $(settings.container).offset().top;
				}

				return fold >= $(element).offset().top + settings.threshold
						+ $(element).height();
			};

			$.leftofbegin = function(element, settings) {
				var fold;

				if (settings.container === undefined
						|| settings.container === window) {
					fold = $window.scrollLeft();
				} else {
					fold = $(settings.container).offset().left;
				}

				return fold >= $(element).offset().left + settings.threshold
						+ $(element).width();
			};

			$.inviewport = function(element, settings) {
				return !$.rightoffold(element, settings)
						&& !$.leftofbegin(element, settings)
						&& !$.belowthefold(element, settings)
						&& !$.abovethetop(element, settings);
			};

			/* Custom selectors for your convenience. */
			/* Use as $("img:below-the-fold").something() or */
			/* $("img").filter(":below-the-fold").something() which is faster */

			$.extend($.expr[":"], {
						"below-the-fold" : function(a) {
							return $.belowthefold(a, {
										threshold : 0
									});
						},
						"above-the-top" : function(a) {
							return !$.belowthefold(a, {
										threshold : 0
									});
						},
						"right-of-screen" : function(a) {
							return $.rightoffold(a, {
										threshold : 0
									});
						},
						"left-of-screen" : function(a) {
							return !$.rightoffold(a, {
										threshold : 0
									});
						},
						"in-viewport" : function(a) {
							return $.inviewport(a, {
										threshold : 0
									});
						},
						/* Maintain BC for couple of versions. */
						"above-the-fold" : function(a) {
							return !$.belowthefold(a, {
										threshold : 0
									});
						},
						"right-of-fold" : function(a) {
							return $.rightoffold(a, {
										threshold : 0
									});
						},
						"left-of-fold" : function(a) {
							return !$.rightoffold(a, {
										threshold : 0
									});
						}
					});

		})(jQuery, window, document);
	}
});